Every year, countless medications are prescribed to millions of patients to address a wide variety of medical conditions. It is often difficult, however, for physicians to ensure that appropriate dosages of prescribed medications are actually taken by their patients at the appropriate times. Many patients simply fail to take prescribed drugs—sometimes intentionally (perhaps because they want to avoid perceived side effects of the drugs)—sometimes unintentionally (perhaps because they simply forget to take the drugs or run out of the drugs). In other cases, the prescribed drug is taken, but with an incorrect dosage level. This may occur because the patient believes, contrary to the advice of the physician, that a stronger dosage would be beneficial or, more typically, because the patient has simply forgotten that he or she had already taken the medication and then takes an additional, unnecessary dose. These problems are particularly significant among the elderly, who may have a large number of ongoing prescriptions at any one time and who often show signs of short term memory loss. For many medical conditions, including serious heart conditions such as congestive heart failure (CHF), failure to take the prescribed dosage of the drug in a timely manner can have severe adverse consequences. Accordingly, it would be highly desirable to provide techniques, particularly for the benefit of the elderly, for automatically monitoring prescription drug intake to remind the patient if he or she has failed to take a prescribed drug in a timely manner or to warn the patient if the incorrect drug or incorrect dosage has been taken. It is to this end that the invention is generally directed.
Many elderly patients have implanted medical devices, such as pacemakers or implantable cardioverter defibrillators (ICDs), or are candidates for such devices. Increasingly, such devices are provided with the capability of generating warning signals to alert the patient to adverse medical conditions, such as the onset of particular heart problems, so that medical attention may be sought. See, for example, U.S. patent application Ser. No. 10/603,429, filed Jun. 24, 2003 of Wang, et al., entitled “System and Method for Detecting Cardiac Ischemia Using an Implantable Medical Device”. Depending upon the implanted system, the warning signals may be transmitted to an external bedside monitor for alerting the patient or may be applied internally in the form of a perceptible warning signal generated, for example, by an implanted vibration device. In any case, it would be desirable to equip implantable medical devices with components for automatically monitoring prescription drug intake so that such warning devices can also be used to alert the patient if he or she fails to take a prescribed drug in a timely manner or takes the incorrect dosage of the drug. It is to these specific ends that particular aspects of the invention are directed.